Levosimendan, which is the (−)-enantiomer of [[4-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)phenyl]hydrazono]propanedinitrile, and the method for its preparation is described in EP 565546 B1. Levosimendan is potent in the treatment of heart failure and has significant calcium dependent binding to troponin. Levosimendan is represented by the formula:

The hemodynamic effects of levosimendan in man are described in Sundberg, S. et al., Am. J. Cardiol., 1995; 75: 1061–1066 and in Lilleberg, J. et al., J. Cardiovasc. Pharmacol., 26(Suppl.1), S63–S69, 1995. Pharmacokinetics of levosimendan in man after i.v. and oral dosing is described in Sandell, E.-P. et al., J. Cardiovasc. Pharmacol., 26(Suppl.1), S57–S62, 1995. The use of levosimendan in the treatment of myocardial ischemia is described in WO 93/21921. The use of levosimendan in the treatment of pulmonary hypertension is described in WO 99/66912. Transdermal delivery of levosimendan is described in WO 98/01111. Transmucosal delivery of levosimendan is described in WO 99/32081. Clinical studies have confirmed the beneficial effects of levosimendan in heart failure patients.
Erectile dysfunction is the inability to obtain and sustain sufficient penile erection and is referred to as impotence. It can result from a variety of underlying causes ranging from purely psychogenic to completely physical dysfunctioning. Both surgical and pharmacological therapies have been used in the treatment of impotence.